In a conventional coin processing machine, for example, a plurality of coins collectively put into a coin input port are transported one by one along a coin passage, the authenticity and denomination of each of the coins transported along the coin passage are identified by an identifying portion, and the coins are forwarded to a post-processing portion, in which a sorting mechanism for sorting coins for each denomination in accordance with a result of identification is disposed, to be processed.
In the case where a deformed coin having a deformed shape is included in the coins put into the coin processing machine, since the identifying portion cannot identify the deformed coin, the deformed coin identified as a normal coin is forwarded to the post-processing portion as it is. Thus, there is a possibility that, in the post-processing portion, the deformed coin causes a coin jam or a problem such as mechanical damage.
Thereupon, a deformed-coin detector for detecting a deformed coin transported along a coin passage has been developed. The deformed-coin detector includes a transporting unit for straightly transporting coins in the coin passage at a fixed speed and a line sensor which is arranged along a width direction orthogonal to a coin transporting direction of the coins in the coin passage. In the line sensor, a number of detecting elements capable of detecting a coin are linearly arranged along the width direction of the coin passage and arranged opposite to a surface of the coin transported in the coin passage.
The deformed-coin detector detects the width of a coin in the transporting direction, based on a detection time from start to end of detection of any one, which first detects the coin transported by the transporting unit, of the detecting elements of the line sensor, and a transporting speed of the transporting unit. Additionally, the detector detects the width of the coin in a direction orthogonal to the transporting direction of the coin, based on the distance between the detecting elements, which detect the coin and are farthest from each other among a number of detecting elements of the line sensor. Based on a difference between the width in the transporting direction and the width in the direction orthogonal thereto, it is determined whether the coin is a deformed coin (see, for example, Japanese Laid-Open Patent Publication No. 9-161118 (pages 4-5, FIGS. 1 to 4).